Biggest 'Zoom Lens' in Space Takes Hubble Deeper into the Universe

January 7, 2003: The Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space
Telescope has used a natural "zoom lens" in space to boost its view of
the distant universe. Besides offering an unprecedented and dramatic new
view of the cosmos, the results promise to shed light on galaxy
evolution and dark matter in space. Hubble peered straight through the
center of one of the most massive galaxy clusters known, called Abell
1689. For this observation, Hubble had to gaze at the distant cluster,
located 2.2 billion light-years away, for more than 13 hours. The
gravity of the cluster's trillion stars — plus dark matter — acts as a
2-million-light-year-wide "lens" in space. This "gravitational lens"
bends and magnifies the light of galaxies located far behind it,
distorting their shapes and creating multiple images of individual galaxies.

Q & A: Understanding the Discovery

1.
What does the image reveal?

The photo shows a massive cluster of yellowish galaxies that are seemingly caught in a red and blue spider web of eerily distorted background galaxies. Some of the faintest objects in the picture are probably more than 13 billion light-years away. Interspersed with the foreground cluster are thousands of galaxies, which are "lensed" images of the galaxies in the background universe. The picture is an exquisite demonstration of Albert Einstein's prediction that gravity warps space and distorts beams of light.

Though gravitational lensing has been studied by Hubble and by ground-based observatories, this phenomenon has never been seen before in such detail. The ACS picture reveals 10 times more arcs, which represent distant galaxies, than would be seen by a ground-based telescope.

Detailed analysis of the Hubble image promises to shed light on galaxy evolution and the mystery of dark matter.